Optimates and populares
Populares ("Favoring the people", singular popularis) were aristocratic leaders in the late Roman Republic who tended to use the people's assemblies in an effort to break the stranglehold of the Senate on political power. They were opposed by the conservative Optimates.
The populares wanted to strengthen the power of the plebs, sharing riches of the nobility with the people, granting free bread and similar to the poor and resisting too much outbred slavery, since slavery took jobs from free but poor citizens. Wanting to make Rome more of a "people's" republic, the populares were popular among the people, granting the power of people's tribunes and weakening the nobles senate.
Popularis plans included some moving of Roman citizens to provincial colonies; expansion of citizenship to communities outside of Rome and Italy; and modification of the grain dole and monetary value. The populares' cause reached its peak under the dictatorship of Julius Caesar, the most avid leader of the populares. After the creation of the Second Triumvirate (43 BC–33 BC), the cause of the populares was essentially lost in the following power struggle.
Besides Caesar, notable populares included the Gracchi Brothers, Gaius Marius, Publius Clodius Pulcher, and (during the First Triumvirate) Marcus Licinius Crassus and Pompey. Pompey eventually became more and more of a conservative optimate.